Liquid-sealed lifter roof for fluid storage apparatus



March 27, 1951 J. H. WIGGINS 2,546,572

LIQUID-SEALED LIFTER RooF FoR FLUID STORAGE APPARATUS Filed Feb. 15, 1946 INVENTOR JOHN H. W/ G/NS H TTOHNEY Patented Mar. 27, 1951 UNITED STATES PATENT OFFICE,

LIQUID-SEALED LIFTER ROOF FOR FLUID STORAGE APPARATUS John H. Wiggins, Chicago, Ill.

Application February 13, 1946, Serial No. 647,384

1 Claim, 1

This invention relates to fluid storage apparatus of the type that consist of a tank or equiva-- lent stationary container having a side wall, a lifter roof or vertically movable roof for said tank, provided with a depending skirt or sidewall portion arranged in telescopic relation withv the tank side wall, and a gas-tight seal between the tank side wall and the co-acting side wall portion of" the vertically-movable roof.

The main object of my present invention is to provide a fluid storage apparatus of the general type above mentioned, that is equipped with a liquid seal, which is of such design or construction that it will maintain a gas-tight joint between the tank side wall and the side wall portion of the vertically-movable roof, even though rain water or water condensation, in considerable volume, enters the reservoir which holds the sealing liquid.

Another object is to provide a liquid-sealed, lifter type tank roof, which is of such design or construction that it is not necessary to employ' a depending, heavy weather shield on the roof, disposed so as to surround, extend over, or cover the reservoir which holds the sealing. liquid.

And still another object of my invention is to provide a liquid seal for a vertically-movable tank roof or equivalent element, comprising a reservoir containing a body of oil or similar sealing liquid that will not freeze or evaporate. rapidly, and a novel automatic water outlet for discharging or getting rid of rain water or water condensation that enters said reservoir and separates from the sealing liquid therein by reason of the greater specific gravity of said water. Other objects and desirable features of my invention will be hereinafter pointed out.

Figure l of the drawings is a vertical transverse sectional view of a fluid storage apparatus constructed in accordance with my invention, and

Figure 2 is an enlarged fragmentary vertical sectional view, illustrating one type of automatic drain that can be used to prevent rain water from collecting in or building up in the reservoir which holds the sealing liquid.

I have herein illustrated my invention embodied in an apparatus that is primarily adapted for storing oil and other volatile liquids, and which comprises the following parts: A tank provided with a stationary side wall 5, a lifter roof or vertically-movable roof 2, for said tank, provided with a depending skirt or side wall 3, arranged in telescopic relationship with the tank side wall 1, and an annular trough or reservoir 4, extending circumferentiall'y around. the tank side wallat or near the top edge. of same.v and: containing oil or some other suitable sealing liq: uid x of a similar nature that will maintain a gas-tight'joint between the tank side wall I. and the depending sidev wall portion 3- of the rootwhen the roof rises and falls to vary the volumeof the gas space of the apparatus.

One of. the main purposes of. my invention is to overcome the necessity'of equippinga liquid sealed lifter roof with a weather shield that is relied upon to prevent rainwater from. entering the reservoir. which. holds thev sealing liquid, as such a Weather shield increases the cost of the roof, and as it must telescope over and surround the sealing liquid reservoir, itprevents easy aocessv to said reservoir and to: the side wall portion of the roof when it become necessary to inspect, paint, or otherwise treat or service. thesealing means. for the roof. To this end; I. construct. my improved apparatus in such a manner that: any rain water or water condensation which entersthe sealing liquid reservoir'wi'llbe automatically discharged from said reservoir, thereby effectively preventing rain water from interfering with: the proper. functioning of; the sealing means that is relied upon to maintain a tight joint between thetank side Wall and the. co-acting: side wall portion. of the roof. This result can be attained; in various ways, or bymeans of, various kinds of water discharge devices-1 In the form of my inventionherein shown, the reservoir 4 is provided with an. inverted syphon drain: formed by a vertically-disposed U-tube having a shortleg 5: attached tot-he bottomiof the reservoir 4, and a long leg 6 whose upper end terminates at a point below the top edge of the outer side wall of the reservoir 4 which holds the sealing liquid. Any rain water which enters the open upper end of the reservoir 4 separates from the sealing liquid x by reason of the greater specific gravity of said water, and upon reaching the bottom of the reservoir, said water immediately escapes from the reservoir by passing first downwardly through the short leg 5 of the U-tube, and thence upwardly through the long leg 6 of the U-tube. When the apparatus is first put into operation, the U-tube is filled with water. Thereafter, oil or other suitable sealing liquid as is introduced into the reservoir 4. Depending upon the specific gravity of the oil 9:, said oil will flow down into the right hand leg 5 of the U-tube, a certain approximate distance, thus creating an oil leg, represented by the dot and dash line I in Figure 2, that balances a water leg, represented by the dot and dash line Il in Figure 2. If thereafter additional rain water enters the reservoir 4, said additional water, upon entering the right hand leg of the U-tube, will rise and build up in said right hand leg to a height above the bottom or lower end of the oil leg I00, whereupon the syphon will be unbalanced and sufficient water will rise in the left hand leg 6 of the U-tube and escape from the upper end of same, to restore the equilibrium of the oil leg I00 and water leg IOI.

Irrespective of the quantity of or volume of water that enters the oil reservoir 4 and separates from the sealing liquid :v, water can never remain in or build up in the water reservoir 4. This is due to the fact that (a) The right hand leg of the U -tube is made of such length that it will comprise an upper oilreceiving portion of substantial length, represented by the dot and dash line I02, and a lower water-receiving portion of substanial length, represented by the dot and dash line I03, and to the fact that (b) The upper end of the left hand leg 6 of the U-tu-be terminates at a point far enough below the top edge of the reservoir to insure that the water leg IIJI will be shorter than the oil leg I00, the reference character I04 being used in Figure 2 to designate the distance between the top of the water leg WI and the top of the oil leg I00.

Usually, the said distance I04 will be about 1 ft., and the right hand leg 5 of the U-tube will be made of such length that its oil-receiving portion I02 will be from 2 ft. to 3 ft. long and its water-receiving portion I03 will be a trifle longer. The essential thing is that the right hand leg 5 of the U-tube be of sufiicient length to provide for changes in the specific gravity of the sealing oil a: resulting from changes in temperature, and to provide for variations in the pressure in the gas space, even a change from positive to minus pressure. For example, if a change in temperature produces a change in the specific gravity of the sealing oil, the length of the column of oil in the upper oil-receiving portion I02 of the right hand leg of the U-tube will vary, but it will never diminish to an extent suflicient to permit the column of water on which it floats to rise in said leg and enter the reservoir 4. Similarly, when a minus pressure is created in the gas space of the apparatus, said minus pressure is exerted on the sealing liquid .1: in the reservoir, with the result that the oil in the upper portion I02 of the right hand leg of the U-tube rises and falls, but under no condition, can the oil in said portion I02 rise high enough to cause water in the right hand leg 5 of the U-tube to enter the reservoir 4. Thus, it will be seen that an inverted syphon drain having parts of the relative proportions and arrangement above described, effectively takes care of all changes in the condition of the sealing liquid, all changes in the internal pressure of the gas space of the apparatus, and also all variations in the volume or quantity of any water that enters the reservoir 4 which holds the sealing liquid. Usually, the peripheral portion of the roof 2 will project radially beyond the reservoir 4 sufficiently to insure that the rain water which drips from the drip flange 2 on the peripheraledge of the roof will be discharged at a point beyond or outside of the reservoir 4, but there is no portion on the roof that performs the function of a weather shield employed to excluderain from the reservoir 4 in any or all positions of the roof. Accordingly, by eliminating a weather shield, I reduce the weight and cost of the roof, and I provide easy access at all times to the side wall portion 2 of the roof and interior of the reservoir 4 for inspecting, painting, or otherwise servicing said parts.-

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

A fluid storage apparatus, comprising a tank having a side wall portion, a vertically-movable roof provided with a depending side wall portion arranged in telescopic relationship with the tank side wall, a reservoir extending circumferentially around the tank side wall and adapted to contain a sealing liquid in which the depending side wall portion of the roof is immersed, and an inverted syphon drain for said reservoir formed by a vertically-disposed U-shaped member having a short leg attached to the bottom of said reservoir and a long leg whose upper end terminates at a point below the level of the sealing liquid in said reservoir, said short leg being of sufficient length to hold a column of sealing liquid of substantial depth arranged above a column of water.

JOHN H. WIGGINS.

REFERENCES CITED UNITED STATES PATENTS Name 7 Date Staber Nov. 17, 1936 Number 

